“An Adaptive Filter For Clutter Suppression In Doppler Radar System”

Abstract

The clutter return presents a severe problem in detection of target in radar systems. Conventional frequency selective filter fails to distinguish clutter and echo form target since they have same frequency spectrum. This paper proposes an adaptive clutter suppression scheme. An adaptive digital filter processes a signal by employing an architecture having time varying parameters. The approach used in this paper is able to overcome the inherent limitations of conventional clutter cancelling techniques (e.g. Moving target indicator, delay line canceler etc.) having predefined filter coefficients. A LMS algorithm based adaptive FIR filter has been implemented for filtering in order to suppress clutter. Matlab simulation has been done to compare the performance of the adaptive filter with that of delay line cancelers. The result shows that the adaptive filter has better frequency response in the pass band than that of delay line cancelers. The filter have been tested with real micro rain radar data using two different scenarios, using rain phenomenon once as target and then as clutter. In both scenarios the filter has been able to cancel clutter.